1. Field of the Invention
The present invention relates to a method of producing a flexible heat exchanger for absorbing heat from or delivering heat to its surroundings, a device for carrying out the method, a flexible device produced in accordance with the method, and the use of a resilient, plastic mat in the production of said heat exchanger.
2. Discussion of the Background
The heat exchanger may conveniently be used, e.g., as an absorber in a solar energy arrangement, or as a heat exchanging element in a heat exchanging system, or for heating water in desalination processes, or in other applications where a fluid is desired to flow separately from the surroundings for the purpose of absorbing or emitting heat.
The use of flexible rubber material in solar energy absorbing systems has been found more beneficial than the use of rigid materials, such as steel, aluminium, etc. One advantage is that internal deposits or coatings in solid form, e.g. salt, lime or crystalline deposits, can be removed more effectively when cleaning the absorber, since it can be bent and folded during the process, therewith loosening the internal deposits from the walls of the absorber and enabling the deposits to be crushed and readily washed away.
Known flexible absorbers are typically comprised of two pieces of rubber fabric that are placed one upon the other and then mutually joined along their respective edges, normally by vulcanization. The resultant unit is inflated so as to separate the mantle surfaces of the rubber-fabric pieces and hold said pieces apart while a newly heated moulding tool presses the fabric pieces together at those positions where it is wished to join said pieces together, e.g. at positions at which channels will be formed internally of the absorber.
This provides an inexpensive product in comparison with steel or aluminum absorbers. Despite this, however, the actual production of the absorber is nevertheless expensive, due to the relatively long vulcanizing or curing times required, among other things.
Leakage problems have also occurred at the inlet and outlet of the absorber, where rigid pipe connectors, normally steel connectors, have been vulcanized firmly to the flexible absorber.
A rubber absorber is also relatively heavy and has a limited useful life, since the rays of the sun which the absorber is intended to capture tend to decompose the rubber.
Metal and rubber absorbers also have a significant material thickness, which shall be heated together with the fluid. A thick material in the absorber walls imparts inertia to the absorber when heating from cold conditions, e.g. after a large cloud has passed.
Accordingly, an object of the present invention is to overcome these drawbacks and to provide a flexible heat-exchanger that is light in weight, mechanically strong and that can be produced in a rational manner.
This object is achieved with the invention first mentioned above having the characteristic features according to one of the accompanying independent Claims.
Further developments of the invention are set forth in the following dependent Claims.
Further features of the invention and advantages afforded thereby will be evident from the following description of a solar energy heating system that includes a flexible heat-exchanging device according to one embodiment of the invention, said embodiment constituting solely an example of the invention and having no limiting effect on the inventive scope. To facilitate an understanding of the text, reference signs have been included in the Figures of the drawings, in which equivalent or similar parts have been identified by the same reference signs.